Building a hot vintage engine with Jonny69

[Jonny69]

About a month ago the engine in my old Pop expired. It was kind of expected because it had stood for about 15-20 years before I had it and I just put some petrol in it, cranked it over and it ran. Well it was getting slowly worse, lots of noise from the top end and it was weeping a bit of water. Then I took it on a long run on the motorway and the obviously very perished rear seal gave up and I was losing oil out the back.

The decision was taken to convert it to a later lump, out of a car called a 100E because it's a fairly easy swap onto the original gearbox and it's free extra horsepower for the same displacement, 1172cc. Plus I had one that was overbored, cammed, flowed and breathed on and it was going to liven the car up quite a lot. Given a bit of time I realised I really haven't got enough time to do it when my Anglia needs some time so a quick change of plan and I decided to work the original lump. It would all need a rebuild anyway so it's not much more to slip in a cam, do a bit of flow work and get the head ground down for some more compression.

So I'll be needing some vintage speed equipment. Aquaplane inlet manifold, check:



Aquaplane exhaust manifold, check:



Twin carbs, check:



A trolley full of junk parts, check:



And now I need to do much head scratching because everybody who knows anything about these engines is now dead so I'm pretty much on my own!

Saturday afternoon me and a mate hoiked the old engine out the car. Literally took the radiator out, took the grill shell off the front of the car and lugged it out with a tow rope and a chunky luggage strap. This is the offending item:



I have a spare engine I picked up for £30 that I'm using as a test bed. I was hoping it might be a runner but it has had water in it and the valve guides are shot but it's a good block to experiment on:



That's half a shopping trolley it's sat in, they make great engine trolleys. Please note: Sainsburys charge £1 for their trolleys but they are free at Waitrose. I stole mine from Sainsburys because I feel by not charging me Waitrose has trusted me not to steal their trolleys. I will honour that trust. Sainsburys on the other hand has made me feel like a petty theif so I honoured that too and nicked their trolley. And very nice it is too.

Here's my hot 100E engine. Head off and I'm going to be taking the cam out as it's the same fit for both engines. This one is a re-ground high lift item. Note how the valves are next to the bores, it's called a sidevalve engine and most vintage engines are this design:



First on the priorities is to increase the compression. These old engines have super low compression so they can run on ultra low grade petrol. The Pop engine is 6:1 and the later 100E engine is 7:1, both are too low really and it can be increased by machining the head down. With the extra lift of the cam I need to be sure that the valve isn't going to come into contact with the head if I start machining the face, because it's going to decrease the height of the chamber:



I've measured it in the 100E block and it comes to 9.5mm, direct lift from the cam so it will be the same in the other engine. Next because the inside of the chamber is rounded at the top I need to know I have enough clearance at the sides of the valves when they are open:

[Jonny69]

Here's checking the standard lift, I measured to be 7.35mm so my reground cam is quite bumpy in comparison:



I discovered something interesting. Earlier engines were only 950cc and had a smaller combustion chamber to suit the lower displacement. The stud pattern on the head is the same throughout the range so an easy way to get some more compression I figured is to use an early head on a later engine. Also I'd have to take some 4mm off the metal which is going to make it very thin and probably prone to cracking. The early head would only need about 1mm maximum thus leaving me plenty of metal left.

Here you can easily see the difference, it's about 1/3 smaller which will instantly take it up from 6:1 to around 7.5:1 I worked out. Early head is on the left, later one is on the right:



It's a lot more shallow so I have to check I will have enough clearance once the face is ground. It comes in somewhere between 10mm and 9.5mm so it's going to be close once the headgasket is on.:



I'd also better check it's the same width in case the valves don't fit in across. All ok, the valves are 58mm across and the chamber is over 61mm:



On the chamber on the right hand side where I've cleaned it up you can see there is a bulge either side of the spark plug hole. I am going to get this machined down so that it is flush. That way I can take a bit more meat off the face of the head and hopefully get it up to about 8:1 compression which is plenty for a sidevalve:



Ooh I'd better quickly check it actually fits on the studs, phew that's a bit of luck!



So here's a shot straight down on the bore on my spare engine. I'm going to be doing some flow work here to improve the efficiency. There's a sharp edge on the side of the bore and the plan is to round that off in the area under the combustion chamber. This is an old well proven trick from years gone past and I am going to follow that advice. Gas flows over a smooth curve easier than it does a sharp edge, it's quite simple:



So it's too much for me now, I need to see a mockup...

[Jonny69]

And finally I decided to get the head off the engine I'm going to be using. This is a matter of clubhammering the hell out of it, driving wedges in the side, wriggleing and more hammering. It gets well rusted onto those studs. Here I've numbered the valves so they all go back in their correct holes. I'll be regrinding them but it helps if they go back where they came from:



So tomorrow I'll be talking to my mate who is going to grind the head and a week later I should be able to fit it. This week with a bit of luck I'll be cleaning it up, flowing it and screwing it back together

[Zirax]

I'll have a proper read tomorrow, but my grandad used to work on these back in the day. He's in his 70s now but used to be an engineer in the RAF as well as a motor mechanic for a good few years. If you need any advice he would love what you are doing and would gladly give you some info from someone who actually worked on them

[Darrin]

This is another one of those times where I wish my father was still alive. He used to race Anglia's in Vancouver MANY years ago. He probably could have spent at least a couple hours reminiscing over your cars and given you quite a few tips on how to get the best performance out of them.

[Jonny69]

I hope to carry that flame forward Darrin. There aren't many people who can still build an engine the old way but it's the only way I know how to do it.

[Darrin]

I agree. I'm still very much old school myself. Give me a set of points and a condenser and I'm happy. Let me rebuild an old NSU side draft over a fuel injection assembly any day.

I agree that the newer systems give better performance and reliability, but I am just more comfortable with full-on mechanical systems (even though I'm an electronics technician). There's just WAY too much PFM in electrical systems nowadays.

And I hope some day to be able to carry on the torch over here. I just wish I still had my Hillman Husky. I'm pretty sure you would have drooled quite heavily over that old Vauxhall engine.

[Justsomebloke]

*Pulls up comfy chair, picks up reading glasses*

I'll be here for the juration matey
Just wish i was close enouth to pop round & get my hands dirty. A retro ride is on the cards for me, it's all i want to be seen in these days & perfect for my current budget
Dunno what yet but i am hankering for a Tina like my old & favourite x car. A Mk2 Tina 1600GT 2 dr with a lovely old crossflow in it to tinker with.
Looking forward to watching your build, good Luck with it


p.s. I'd also like an old Imp with one of those rally x packs on it. Never had one but i have a serious soft spot for rallied up Imps.

[Darrin]

Pikey, you just reminded me of the the Cortina I had at a very young age. Why I couldn't have found it now instead of when I was young and stupid berates on my soul in an uncomfortable way.

[Jonny69]

On with the build...

First task is to get the old head studs out. I would have to hammer the head back on because they are rusted and bent and I don't want that so I'm going to replace them with shiny new straight items. I was a bit worried about them shifting but the oldest trick in the book worked on all of them so I was happy. Basically wind a nut on the thread, hold it with a spanner and crank another nut onto it really tight. Then 99% of the time you can undo the whole thing with the bottom nut:



To get the nut back off is a matter of mole grips round the stud and undo the nut:



Luckily it was only the last one that was REALLY tight and mangled up:



Now I want to take the valves out. I had to buy a slim valve spring compressor to do this because the springs are incredibly small in this engine and my old one wouldn't go in. Normally what you've got is a retainers at the end of the valve with a pair of tapered collets that hold it on the end of the valve. You compress the spring and the two collets pop out and you can withdraw the spring. It's a bit different on this engine because the end of the valve is tapered itself and the retainer has a slot cut out of one side and you have to pull it out with pliers. It's fiddle and requires a bit of brute force:



You have to jam the compressor between the bottom two coils of the valve spring:



Then grab the retainer with a pair of needle nose pliers:



Then pull the valve up like the top picture and get a hold of the spring with pliers and yank it out:



The valve then doesn't just come out because it's tapered at the end so it won't fit through the valve guide. This took a bit of head scratching but the valve guide is in two pieces and is pressed into place. One has to drift it out with a special tool, or in my case a clubhammer and a couple of screwdrivers. This is what it looks like when out:



I spotted a flow improvement opportunity here. Take a look at this very poor photo and you can see the top of the valve guide protrudes right into the port, semi blocking it up:



Well I'm not having that, so it's going on the lathe and it's coming off. There's still plenty of length on it to support the valve so that's free extra flow to me.

Lining up the valve springs I spot a little inconsistency:



Apart from the fact that they are about as strong as radio controlled car springs they are all different lengths so I will replace them all for uprated items. There is no way the standard items will be able to cope with increased revs, these ones are destined for a pair of spring loaded shoes or something.

One major annoyance is that this engine has solid cam tappets and you can't adjust the valve tolerances. To reduce the gap you have to grind the valve seats to make the valve drop down a bit and to increase the gap you have to get the end of the valve stem ground back. This means that as it stands I can't use my high lift cam because I will need different length valves and the process of getting them to the right ground length isn't something I can do at home, which goes against the aim of this project. Luckily Small Ford Spares do aftermarket ajustable tappets which is a lifesaver, by no means cheap, but it means I can use the cam afterall! Phew!